Tested to meet ASTM E595, a standard used by NASA, these compounds produce almost no volatile emissions that could damage sensitive electronics, even in a vacuum. Light passes through them easily, so they’re ideal for protecting solar cells and fiber optics. Made of silicone, these compounds are softer and more flexible than epoxy and urethane compounds. That means they’re better at protecting against shocks and vibration. They also withstand a wider range of temperatures, so you can use them with electronics that heat and cool rapidly. These compounds are excellent electrical insulators, and they’ll shield your components from moisture and dust. However, they don’t hold up well to chemicals or scrapes. They’re also known as RTV (room-temperature vulcanizing).

These compounds are easy to apply in high volumes. Just mix the two parts together and pour them over components inside a container, such as a potting box.

Make repairs or changes to electrical components after they’ve been potted. While most compounds are permanent, these form a gel that bonds to itself, so you can peel it off without damaging your equipment. Often used in junction boxes, they form a water- and dust-proof seal that’s rated IP68 while also providing excellent electrical insulation. Made of silicone, they withstand a wide range of temperatures and are soft and flexible enough to resist shock and vibration. However, they’re not as strong as permanent potting compounds, so they don’t resist scrapes as well as those made of epoxy and urethane. They’re also not as chemical resistant as epoxy and urethane compounds.

These compounds won’t solidify once you open the container, so you have time to make adjustments when applying them. When removing them from your components, they mostly come off in one piece but there might be some residue left over.

Bottle compounds are a better choice for filling up new enclosures than cartridge compounds because you can pour more in at a time. They have a compartment for each component and require mixing.